The described invention relates in general to ventilation systems for use with thermal window units, multi-paned windows, and/or windows having multiple lights, and more specifically to a unidirectional valve and valve system for allowing moisture and humid air to flow out of interior spaces formed between the panes or lights of a multiple glazing unit or similar item.
“Insulated glazing unit” or “insulating glass unit” (commonly referred to as IGU) is a set of two or more lights (i.e., separately framed pieces or panes of glass in a window or door) spaced apart from one another and hermetically sealed to form a single glazed unit with an air space between each light. An IGU typically functions to improve the thermal performance of glass when used in architectural applications. Another name often used in North America is “sealed insulating glass” (abbreviated SIG). The most common IGUs are double glazed, i.e., made with two lights of glass, and are therefore also referred to as “double glazing units” or “DGU” (particularly in Europe). IGUs having three or more lights, i.e. “triple glazing” are sometimes used in colder climates. IGUs are also commonly used as replacement windows.
An IGU made of glass is called insulated glass, referring specifically to the thermal insulating properties of the IGU. Another term used for this technology is “insulating glass” although the glass itself has few insulating properties; rather it is the air space between the glass layers that provides thermal insulation. The air space between the panes or lights may be filled with air or an inert gas like argon or krypton which provides the insulating properties. Typically, the air space is filled with desiccant to reduce condensation and improve insulating performance. Less commonly, most of the air is removed, leaving a partial vacuum, which drastically reduces heat transfer through convection and conduction. This is called evacuated glazing. Insulating “quality” refers to heat flow where the gap between lights is the insulating medium. The gap between panes or lights is usually 12 mm to 20 mm thick; however, the thickness of the gap does impact the insulating properties substantially. An air gap of about 16 mm is considered optimal and is usually recommended for most applications.
A common problem with multiple glazing units (hereinafter referred to as thermal window units) is that over time condensation occurs in the air space between the panes of glass and fogs, stains, or discolors the window thereby diminishing its appearance. One solution to the problem of condensation between window panes is to simply replace the window. However, this solution is costly and time consuming and as such, is usually not desirable. Another solution to the problem involves drilling or cutting a hole in one of the window panes and applying a vacuum to remove the moisture. The hole is then covered or plugged. While this method can be effective, it is often only a temporary fix and in time the method must be repeated when condensation reappears. Another approach to correcting the problem of condensation within thermal window units includes the use of small ventilation units that are inserted into holes drilled in one or more of the window panes. These units provide ventilation to the space between lights or panes; however, they also permit moisture-laden air to flow back into the air space. Therefore, an ongoing need exists for a ventilation system for use with thermal window units that provides for the removal of condensation, but that prevents the flow of moisture-laden air back into the air space between the panes/lights.